Avoid defects in polyurethanes

Avoid defects in polyurethanes

Thursday, 15 May, 2025

Molecular sieves are materials used to remove moisture from air and other gases. For comparison, they can be described as tiny sponges capable of attracting and retaining water molecules, helping to keep environments dry and to protect moisture-sensitive products. Various types of molecular sieves exist, but zeolites are among the most effective.

Zeolites are natural minerals with a crystalline structure, used in applications that require selective absorption of specific gases or vapours.

In polyurethane systems, moisture present in raw materials can react with isocyanates, generating CO₂ bubbles and, consequently, surface defects or curing issues. Moisture may also be present on the substrate to which the polyurethane will be applied.

FINMA-SORB 430 PR is our zeolite-based solution. It is dispersed in 50% castor oil, offering low viscosity and a stable pot life. FINMA-SORB 430 PR is specifically designed for moisture absorption due to its pore size of 3 Å. Larger pore sizes may absorb other molecules, such as nitrogen, which can later be released during application and cause additional issues.

One of the key advantages of FINMA-SORB 430 PR in paste form over other powdered zeolites is that the active material is consistently protected from exposure to ambient moisture, thereby preserving its full moisture absorption capacity.

Fuente: Link

Its main applications are in moisture-sensitive systems, such as two-component PU systems, PU coatings and PU-based adhesives and sealants.

Do not forget that here at Comindex we can support you throughout your process. Simply contact our team of technical sales advisors.

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